Answer: Broad stock market index (e.g., S&P 500).

**Explanation:** - **Option A (Incorrect):** The Consumer Price Index (CPI) is a lagging indicator, as it reflects changes in inflation, which typically adjusts after economic activity has already occurred, particularly in more stable sectors like services. - **Option B (Correct):** A broad stock market index, such as the S&P 500, is a leading economic indicator. Positive movements in this index often precede increases in aggregate economic activity, signaling future economic growth. Similarly, indices like the Euro Stoxx Equity Index serve as leading indicators in the Eurozone. - **Option C (Incorrect):** The Industrial Production Index (IPI) measures industrial output, which is highly volatile and is classified as a coincidental indicator by the Conference Board in the United States, not a leading one.

Author: LeetQuiz Editorial Team